Fusion implant and method of making same

Abstract

The present invention provides an implant for use in fusing adjacent bony structures. The implant comprises at least one structural member combined with at least one flexible planar member to retain the at least one structural member to form the implant.

1. An implant for use in fusing adjacent bony structures comprising at least one structural member combined with at least one flexible planar member forming a flexible outer layer wrapped around the at least one structural member to retain the at least one structural member to form the implant, and wherein said implant includes at least one opening extending continuously through the entire implant, said opening including an inner wall extending from a first surface of the implant for contacting a first one of said adjacent bony structures to a second surface of the implant for contacting a second one of said adjacent bony structures, said inner wall defined by portions of said flexible outer layer and of said at least one structural member. 
     
     
       2. The implant of  claim 1  wherein the at least one structural member comprises at least one shape selected from the group consisting of particles, strips, blocks, and beams. 
     
     
       3. The implant of  claim 1  wherein the at least one structural member comprises at least one material selected from the group consisting of bone, metal, ceramic, carbon and polymer. 
     
     
       4. The implant of  claim 1  wherein the at least one structural member comprises at least one material selected from the group consisting of polyethylene, polyester, polyglycolic acid, polylactic acid, polytetrafluroethylene, polyaryletherketone, and polyetheretherketone. 
     
     
       5. The implant of  claim 1  wherein the at least one flexible planar member comprises at least one shape selected from the group consisting of sheet, block, foam, woven fabric, non-woven fabric, membrane, and mesh. 
     
     
       6. The implant of  claim 1  wherein the at least one flexible planar member comprises at least one material selected from the group consisting of body tissue, resorbable polymer, nonresorbable polymer, and metal. 
     
     
       7. The implant of  claim 1  wherein the at least one flexible planar member comprises at least one material selected from the group consisting of fascia, skin, pericardium, partially demineralized bone, fully demineralized bone, cartilage, tendon, and ligament. 
     
     
       8. The implant of  claim 1  wherein the flexible outer layer retains a plurality of structural members to maintain them in a predetermined form. 
     
     
       9. The implant of  claim 1  wherein the structural member has a longitudinal axis and the flexible outer layer retains the structural member with its axis in a predetermined orientation. 
     
     
       10. The implant of  claim 1  wherein the at least one structural member comprises a plurality of pieces of bone. 
     
     
       11. The implant of  claim 10  wherein the individual pieces of bone have less than a predetermined minimum load bearing capacity and the combined pieces form an implant that achieves a predetermined capacity greater than the predetermined minimum load bearing capacity. 
     
     
       12. The implant of  claim 11  wherein the individual pieces of bone have a predetermined geometry. 
     
     
       13. The implant of  claim 12  wherein the individual pieces of bone comprise cortical bone harvested from a donor bone having a longitudinal axis, the individual pieces of bone having a thickness, measured radially from the longitudinal axis of the donor bone, less than 2 mm thick. 
     
     
       14. The implant of  claim 10  wherein the pieces of bone include at least one shape selected from the group consisting of particles, strips, blocks, and beams. 
     
     
       15. The implant of  claim 10  wherein the pieces of bone comprise cortical bone for achieving a predetermined load-bearing capability in the implant. 
     
     
       16. The implant of  claim 15  wherein the pieces of bone further comprise cancellous bone. 
     
     
       17. The implant of  claim 16  wherein the individual pieces of bone are further interconnected by at least one means selected from the group consisting of chemical and mechanical means. 
     
     
       18. The implant of  claim 17  wherein the individual pieces of bone are interconnected by at least one means selected from the group consisting of pinning, suturing, pressing, incorporating a binding agent, collagen crosslinking, and interlocking mechanical engagement. 
     
     
       19. The implant of  claim 18  wherein the individual pieces of bone are interconnected with at least one material selected from the group consisting of fibrin glue, cyanoacrylate, epoxy, polymethylmethacrylate, and gelatin. 
     
     
       20. The implant of  claim 10  wherein the at least one flexible planar member comprises at least one shape selected from the group consisting of sheet, block, foam, woven fabric, non-woven fabric, membrane, and mesh. 
     
     
       21. The implant of  claim 10  wherein the at least one flexible planar member comprises at least one material selected from the group consisting of body tissue, resorbable polymer, nonresorbable polymer, and metal. 
     
     
       22. The implant of  claim 10  wherein the at least one flexible planar member comprises at least one material selected from the group consisting of fascia, annular fibrosus, skin, pericardium, partially demineralized bone, fully demineralized bone, cartilage, tendon, and ligament. 
     
     
       23. The implant of  claim 10  wherein the flexible planar member further comprises different types of elongated, planar material. 
     
     
       24. The implant of  claim 23  wherein one type of planar material is utilized in one dimension while a different type of planar material is utilized in another dimension. 
     
     
       25. The implant of  claim 10  wherein the flexible outer layer retains the bone pieces in a predetermined form. 
     
     
       26. The implant of  claim 25  wherein the predetermined form comprises at least one form selected from the group consisting of substantially rectangular prisms, spheres, and hemispheres, and combinations thereof. 
     
     
       27. The implant of  claim 10  wherein the flexible outer layer and said plurality of pieces of bone combine to provide a load bearing implant body sized and configured for insertion between adjacent first and second vertebrae. 
     
     
       28. The implant of  claim 27  wherein the at least one opening is sized such that it is smaller than the bone pieces such that the bone pieces are contained by the flexible outer layer. 
     
     
       29. The implant of  claim 27  wherein a retaining material is inserted within the at least one opening to bind with the pieces of bone to retain them within the at least one opening. 
     
     
       30. The implant of  claim 29  wherein the retaining material comprises at least one material selected from the group consisting of bone paste, collagen, gelatin, polymers, fibrin, and settable ceramics. 
     
     
       31. The implant of  claim 27  wherein the flexible planar member comprises a plurality of layers with the bone pieces being positioned between the layers. 
     
     
       32. The implant of  claim 27  wherein the at least one opening comprises an inner wall extending through the entire implant from a first implant surface configured to contact the first vertebra to a second implant surface configured to contact the second vertebra. 
     
     
       33. The implant of  claim 32  wherein the inner wall is formed through a first layer of the flexible outer layer, through the bone pieces and through a second layer of the flexible outer layer. 
     
     
       34. The implant of  claim 32  wherein the opening and inner wall are formed by at least one operation selected from the group consisting of drilling, cutting, and punching. 
     
     
       35. The implant of  claim 32  wherein the opening and inner wall comprise a hollow member having a wall defining the opening and inner wall. 
     
     
       36. The implant of  claim 35  wherein the hollow member comprises at least one biocompatible material capable of preventing the passage of the bone pieces through its structure. 
     
     
       37. The implant of  claim 27  further comprising a bone growth-promoting material inserted within the at least one opening. 
     
     
       38. The implant of  claim 37  wherein the bone growth-promoting material comprises at least one material selected from the group consisting of bone paste, cancellous bone, bone chips, bone morphogenic protein (BMP), LIM mineralization protein (LMP), platelet derived growth factors, bone marrow aspirate, stem cells, biologic growth factors, and combinations thereof. 
     
     
       39. The implant of  claim 10  further comprising a securing mechanism to insure that the flexible outer layer maintains a bone-retaining position. 
     
     
       40. The implant of  claim 39  wherein the securing mechanism attaches one portion of the flexible outer layer to another portion of the flexible outer layer. 
     
     
       41. The implant of  claim 39  wherein the securing mechanism comprises at least one mechanism selected from the group consisting of sutures, wires, pins, straps, clamps, staples, heat bonding, cross-linking, ultrasonic welding, and adhesives. 
     
     
       42. The implant of  claim 39  wherein the securing mechanism connects a plurality of implants to form a larger implant. 
     
     
       43. The implant of  claim 39  wherein the securing mechanism comprises a material that resorbs within the body after a predetermined period of time. 
     
     
       44. The implant of  claim 10  wherein the bone pieces and flexible planar member form a plurality of layers. 
     
     
       45. The implant of  claim 44  wherein the flexible outer layer completely encompasses the bone pieces except at said at least one opening. 
     
     
       46. The implant of  claim 45  wherein the implant comprises cancellous bone pieces and cortical bone pieces rolled up within at least one flexible planar member. 
     
     
       47. The implant of  claim 46  wherein the cancellous bone pieces are located near the center of the roll and the cortical bone pieces are located near the periphery of the roll. 
     
     
       48. The implant of  claim 44  wherein the layers are oriented in an orientation selected form the group consisting of substantially horizontal, substantially vertical, substantially curvilinear, and substantially planar. 
     
     
       49. The implant of  claim 44  wherein at least one layer primarily provides structural support and at least one layer primarily provides a bone fusion material. 
     
     
       50. The implant of  claim 49  wherein the at least one structural support layer comprises cortical bone and the at least one fusion layer comprises cancellous bone. 
     
     
       51. The implant of  claim 44  wherein the layers are formed radially relative to a center of the implant, the bone pieces comprising a plurality of bone pieces with differing load carrying capacity, the bone pieces being arranged in the radial layers with bone pieces having lower load carrying capacity nearer the center and bone pieces with higher load carrying capacity further from the center. 
     
     
       52. The implant of  claim 44  wherein at least one layer of said plurality of layers comprises exposed bone at an edge to promote fusion of adjacent bony structures through the layer. 
     
     
       53. The implant of  claim 9  wherein the at least one flexible planar member comprises a plurality of layers and the at least one structural member is positioned in at least one opening through the layers. 
     
     
       54. The implant of  claim 53  wherein the at least one structural member is positioned substantially normal to the at least one planar member. 
     
     
       55. The implant of  claim 9 , wherein said at least one structural member comprises a plurality of pieces of bone. 
     
     
       56. The implant of  claim 55  further comprising a bone growth promoting material within the at least one opening. 
     
     
       57. The implant of  claim 53  wherein the at least one structural member fixes the plurality of layers of flexible planar members relative to each other. 
     
     
       58. The implant of  claim 53  wherein at least one layer of bone pieces is positioned between the layers of flexible planar members. 
     
     
       59. The implant of  claim 9  wherein the at least one structural member comprises a biocompatible material capable of withstanding a predetermined load. 
     
     
       60. The implant of  claim 59  wherein the at least one structural member comprises at least one structure selected from the group consisting of bone members, polymer members, resorbable polymer members, and combinations thereof. 
     
     
       61. The implant of  claim 59  wherein the at least one structural member comprises at least one material selected from the group consisting of polyethylene, polyester, polytetrafluroethylene, polyaryletherketone, polyetheretherketone, polylactic acid, polyglycolic acid, carbon, and combinations thereof. 
     
     
       62. The implant of  claim 1  further comprising a fixation device attached to said adjacent bony structures to limit the relative motion between them. 
     
     
       63. The implant of  claim 62  wherein the fixation device substantially prevents all relative motion between the adjacent bony structures. 
     
     
       64. The implant of  claim 62  wherein the fixation device allows a predetermined amount of relative motion between the adjacent bony structures during the fusion process. 
     
     
       65. The implant of  claim 62  wherein the fixation device is selected from the group consisting of plates, internal or external rod systems, cable systems, cerclage systems, screws, and combinations thereof. 
     
     
       66. A load bearing implant for use in fusing adjacent bony structures comprising: a plurality of bone pieces; and a flexible outer layer formed with at least one flexible planar member, the flexible outer layer wrapped around and containing the bone pieces; and said implant having a compressed spherical form substantially similar to the shape of a human spinal disc, and wherein the flexible planar member includes at least one opening to permit fusion of the adjacent bony structures through the implant, said opening including an inner wall extending from a first surface of the implant for contacting a first one of said adjacent bony structures to a second surface of the implant for contacting a second one of said adjacent bony structures, said inner wall defined by portions of said flexible planar member and of said bone pieces. 
     
     
       67. The implant of  claim 66  wherein the bone pieces comprise cortical bone. 
     
     
       68. A load bearing implant for use in fusing adjacent bony structures comprising:
 load bearing means for supporting said adjacent bony structure in spaced relationship; 
 retaining means for retaining the load bearing means in a predetermined orientation, said retaining means wrapped around said load bearing means; and said implant including at least one opening extending continuously through the entire implant, said opening including an inner wall extending from a first surface of the implant for contacting a first one of said adjacent bony structures to a second surface of the implant for contacting a second one of said adjacent bony structures, said inner wall defined by portion of said retaining means and of said load bearing means. 
 
     
     
       69. A system for use in fusing adjacent bony structures, comprising:
 a plurality of bone pieces; 
 at least one flexible planar member forming a flexible outer layer wrapped around and substantially retaining the plurality of bone pieces; 
 said plurality of bone pieces and flexible outer layer incorporated in an implant having at least one opening extending continuously through the entire implant; said opening including an inner wall extending from a first surface of the implant for contacting a first one of said adjacent bony structures to a second surface of the implant for contacting a second one of said adjacent bony structures, said inner wall defined by portions of said flexible layer and of said plurality of bone pieces; and 
 a fixation device attachable to the adjacent bony structures and having a structure to limit relative motion between the adjacent bony structures. 
 
     
     
       70. An implant for use in fusing adjacent bony structures comprising:
 at least one retaining member having a first load carrying capacity; 
 at least one structural member having a second load carrying capacity greater than the first load bearing capacity, the retaining member wrapped around and retaining the structural member in a predetermined orientation relative to the adjacent bony structures; and 
 said implant having at least one opening extending continuously through the entire implant, said opening including an inner wall extending from a first surface of the implant for contacting a first one of said adjacent bony structures to a second surface of the implant for contacting a second one of said adjacent bony structures, said inner wall defined by portions of said at least one retaining member and of said at least one structural member. 
 
     
     
       71. An implant for use in fusing adjacent bony structures comprising at least one structural member combined with at least one flexible planar member forming a flexible outer layer wrapped around and retaining the at least one structural member to form the implant, wherein the at least one structural member comprises a plurality of pieces of bone, wherein the implant further comprises at least one opening to permit fusion of the adjacent bony structures through the implant, and wherein the at least one opening comprises an inner wall extending through the entire implant. 
     
     
       72. The implant of  claim 71  wherein the opening and inner wall are formed by at least one operation selected from the group consisting of drilling, cutting, and punching. 
     
     
       73. The implant of  claim 71  wherein the opening and inner wall comprise a hollow member having a wall defining the opening and inner wall.